DMS

Question 1

name three extrinsic causes of tooth discolouration

Answer 1

smoking
chlorhexidine
iron supplements

Question 2

name three intrinsic causes of tooth discolouration

Answer 2

fluorosis
tetracycline
non-vitality

Question 3

what are the two types of tooth whitening

Answer 3

external vital bleaching
internal non-vital bleaching

Question 4

how does bleaching work on external vital tooth whitening

Answer 4

the discolouration is caused by chromogenic products produced
bleaching oxidises the compounds
leads to smaller and less pigmented compounds

Question 5

what is the active agent in external tooth bleaching

Answer 5

hydrogen peroxide

Question 6

name three constituents of bleaching gel used in dentistry

Answer 6

carbamide peroxide
carbopol
urea

Question 7

what does carbamide peroxide break down to produce

Answer 7

hydrogen peroxide and urea

Question 8

what is the use of carbopol in tooth whitening agents

Answer 8

thickening agent so it stays on teeth

Question 9

name four factors that affect tooth bleaching

Answer 9

time
cleanliness of tooth surface
concentration of solution
temperature

Question 10

name four warnings to consent the patient on before undertaking tooth whitening

Answer 10

sensitivity
relapse
colour of restorations
might not work

Question 11

what are advantages and disadvantages of in-office tooth whitening

Answer 11

controlled by dentist
can use heat/ light
expensive
results wear off

Question 12

what is the maximum strength of home tooth whitening remedies

Answer 12

6% hydrogen peroxide

Question 13

how short should teeth whitening thermoplastic trays stop of the gingival margin

Answer 13

1mm

Question 14

what are the instructions for at home bleaching of teeth

Answer 14

brush and floss
load tray with 1mm dot buccally on each tooth
keep in place for at least 2 hours

Question 15

name four examples of when tooth whitening might be indicated

Answer 15

age related darkening
mild fluorosis
post smoking cessation
tetracycline staining

Question 16

how long does it take for sensitivity of bleaching to wear off

Answer 16

2-3 days post bleaching

Question 17

what clinical complication does tooth whitening present

Answer 17

problem with bonding later
residual oxygen from peroxide remains on enamel

Question 18

name three indications of internal bleaching

Answer 18

non-vital tooth
adequate RCT
no apical pathology

Question 19

what are two contra-indications of internal bleaching

Answer 19

heavily restored tooth
staining due to amalgam

Question 20

name a risk of internal bleaching

Answer 20

external cervical resorption due to diffusion of hydrogen peroxide through dentine into periodontal tissues

Question 21

what has to happen to RCT treated teeth when undertaking internal bleaching

Answer 21

remove GP from pulp chamber and 1mm below ACJ
place 1mm RMGIC over the GP to seal canal

Question 22

why is RMGIC added to RCT treated teeth in internal bleaching

Answer 22

to seal dentine and prevent root resorption

Question 23

what is the procedure for internally bleaching teeth

Answer 23

remove filling from access cavity
remove GP from pulp chamber and 1mm below ACJ
place RMGIC over GP
remove dark dentine
etch
place 10% carbamide peroxide in cavity
cotton wool
GIC

Question 24

how many visits does it usually take to reach desired colour with internal whitening

Answer 24

3-4 visits
after 4 visits and no change - it isn’t going to work

Question 25

after how many years should internal bleaching be retreated

Answer 25

every 4-5

Question 26

what is microabrasion

Answer 26

removes discolouration limited to outer layers of enamel

Question 27

what is the procedure for microabrasion

Answer 27

clean teeth and rubber dam 18% HCl and pumice apply to teeth with prophy cup 5 seconds per tooth wash repeat 10 times polish teeth with fluoride prophy paste apply fluoride gel

Question 28

when should microabrasion be reviewed

Answer 28

after 1 month

Question 29

name advantages of microabrasion

Answer 29

quick easy no long term problems

Question 30

name disadvantages of microabrasion

Answer 30

acid sensitivity only works for superficial staining

Question 31

what products cannot be used for anyone under 18 unless intended for preventing disease

Answer 31

0.1-6% hydrogen peroxide

Question 32

what affects your judgement for the restorability of teeth with composite

Answer 32

if tooth can be isolated well with dental dam if subgingival = cannot achieve sub alveolar cavities/ vertical root fractures = unrestorable

Question 33

what is the purpose of camphorquinone

Answer 33

releases free radicals when attacked by blue light which allows addition polymerisation in the resin

Question 34

what is the action of the resin and what material is this usually in composite

Answer 34

usually bis-GMA allows further cross linking of the C-C double bonds which increases molecular weight, strength and viscosity

Question 35

what is the action of filler in composite

Answer 35

increases compressive strength, abrasion resistance and fracture toughness

Question 36

name two materials that filler in composite can be

Answer 36

lithium aluminosilicate borosilicate

Question 37

what is the purpose of low-weight di-methacrylates in composite

Answer 37

used to adjust viscosity and reactivity

Question 38

what is the purpose of silane coupling agent in composite

Answer 38

bi-functional molecule that increases bond of resin and filler particles

Question 39

name the five components of composite

Answer 39

camphorquinone silane coupling agent filler low weight di-methacrylates resin

Question 40

what is the purpose of acid etching

Answer 40

37% acid which is used to remove the smear layer and allow enamel bonding

Question 41

what are millers forceps used for

Answer 41

for holding articulating paper

Question 43

what is flowable composite used for

Answer 43

useful for filling small voids

Question 44

how should you choose a composite shade

Answer 44

without rubber dam (due to dehydration occurring after placement) check shade with and without operating light involve patient in the selection process check contralateral and adjacent teeth

Question 45

what are the overall shades for the different letters for shade matching composites

Answer 45

A - brown B - yellow C - grey D - red

Question 46

what material is used to take a putty matrix

Answer 46

polyvinylsiloxane

Question 47

what is the purpose in incorporating a bevel in a cavity

Answer 47

increases surface area for bonding - cuts dentinal tubules on their longitudinal long axis which improves bonding

Question 48

how does enamel etching work

Answer 48

selectively dissolves enamel rods to create porosities so the resin can penetrate

Question 49

what is a smear layer

Answer 49

created when dentine is cut by hand or rotary instruments - thin layer of cutting debris, saliva and bacteria

Question 50

what is the hybrid layer

Answer 50

layer created when resin infiltrates the surface layer of dentine - strong bond between resin and dentine forms when monomer penetrates dentine

Question 51

what is the function of HEMA

Answer 51

bi-functional molecule used to prime dentine

Question 52

what are the two main types of dental adhesive systems

Answer 52

etch and rinse self etch

Question 53

what occurs in the etch and rinse systems

Answer 53

smear layer removed by acid etch exposing the dentinal tubules

Question 54

what occurs in self etch systems

Answer 54

simultaneously condition and prime enamel and dentine - smear layer is penetrated by self etch primer which infiltrates smear layer and smear plugs

Question 55

three actions of phosphoric acid

Answer 55

removes smear layer demineralises the dentine exposes collagen fibres

Question 56

three actions of dentine bonding agents

Answer 56

remove remaining water prime dentine for resin infiltration (HEMA) allow resin to fill spaces between collagen fibres

Question 57

what is the percentage of monomer to polymer conversion of composite

Answer 57

60%

Question 58

what light range is required for camphorquinone to be activated in light cure composite

Answer 58

430-490nm

Question 59

what are the free radicals in self cure composites that come as 2 pastes

Answer 59

tertiary amine benzoyl peroxide

Question 60

what is C factor in relation to composite

Answer 60

configuration factor ratio of bonded to unbonded surfaces in a cavity and affects shrinking stress

Question 61

name six complications of composite

Answer 61

moisture control over manipulation over/ under etching polymerisation contraction shrinkage stress low wear resistance longer to place

Question 62

why is moisture control required when placing composite

Answer 62

resin composites are hydrophobic - if contaminated this reduces the bond strength between composite and tooth

Question 63

what is the main problem of over manipulation of composite

Answer 63

incorporates air and therefore porosities within the restoration

Question 64

what is the problem of over-etching

Answer 64

causes collapse of the collagen framework so resin cannot penetrate to full depth

Question 65

what is the problem with under etching

Answer 65

not enough enamel has been demineralised for penetration

Question 66

name three effects of polymerisation contraction shrinkage stress

Answer 66

bond failure cuspal deflection post op sensitivity